[¦käun·tər‚səŋk ′bōlt] (design engineering) A bolt that has a circular head, a flat top, and a conical bearing surface tapering in from the top; in place, the head is flush-mounted.
countersunk bolt
countersunk boltA bolt having a circular head with a flat top and a conical bearing surface which tapers in from the top; when in place, the head is flush-mounted.